1. Field of the Invention
This invention relates to the catalytic decomposition of tertiary butyl hydroperoxide. More particularly, this invention relates to a method for the preparation of tertiary butyl alcohol by the catalytic decomposition of tertiary butyl hydroperoxide.
Still more particularly, this invention relates to an improved continuous method for the preparation of tertiary butyl alcohol wherein a solution of tertiary butyl hydroperoxide in tertiary butyl alcohol formed by the reaction of isobutane with oxygen is separated into a tertiary butyl alcohol fraction and a concentrated tertiary butyl hydroperoxide fraction, wherein the concentrated tertiary butyl hydroperoxide fraction is dissolved in a monocyclic aromatic solvent to form a solution, and wherein the solution is charged to a tertiary butyl hydroperoxide decomposition zone together with a phthalocyanine catalyst and substantially selectively decomposed therein to tertiary butyl alcohol.
2. Prior Art
It is known to react isobutane with oxygen, either thermally or catalytically, to form a peroxidation reaction product wherein the principal peroxide that is formed is tertiary butyl hydroperoxide. It is also known to thermally or catalytically decompose the tertiary butyl hydroproxide to form tertiary butyl alcohol.
Taylor et al. U.S. Pat. No. 4,551,553 is directed to a process for the formation of alcohols such as tertiary butyl alcohol by the catalytic decomposition of an organic hydroperoxide such as tertiary butyl hydroperoxide using a binary catalyst composed of a mixture of a ruthenium compound with a chromium compound. It is stated that the use of the binary catalyst eliminates the need for stabilizing ligands.
Klein in U.S. Pat. No. 3,472,876, discloses the use of cobalt diimine chelates to catalyze the reaction of oxygen with an olefin to form an olefin epoxide.
Quin U.S. Pat. No. 2,854,487 discloses a process wherein isopropyl benzene hydroperoxides are catalytically decomposed to form carbonols in the presence of hydrogen and a catalyst composed of palladium supported on activated alumina.
Grane U.S. Pat. No. 3,474,151 discloses that tertiary butyl alcohol starts to dehydrate at 450.degree. C. and to decompose at a "rapid rate"at temperatures above 475.degree. F. Grane discovered, however, that residual quantities of hydroperoxide contaminants present in tertiary butyl alcohol could be thermally decomposed by heating the contaminated tertiary butyl alcohol at a temperature of 375.degree. to 475.degree. F. for about 1 to 10 minutes.
Grane et al. U.S. Pat. No. 4,294,999 discloses a process wherein isobutane is oxidized in a pressured reactor in the presence of a solubilized molybdenum catalyst to provide a mixture of tertiary butyl alcohol, tertiary butyl hydroperoxide, methanol, acetone, and other oxygen-containing compounds. The tertiary butyl hydroperoxide is thermally decomposed under pressure at about 280.degree. F. to provide a tertiary butyl alcohol product containing only residual quantities of tertiary butyl hydroperoxide which are then decomposed in accordance with Grane U.S. Pat. No. 3,474,151 by heating the tertiary butyl alcohol at 375.degree. to 475.degree. for about 1 to 10 minutes. Heating tertiary butyl alcohol containing small amounts of peroxides at high temperatures for even short periods of time to remove the peroxides produces undesirable products such as isobutylene.
Grane et al. U.S. Pat. No. 4,296,262 discloses a related process wherein isobutane is reacted with oxygen in a reaction zone for a residence time of about 1 to 10 hours at a temperature of about 240.degree. to about 340.degree. F. and a pressure of about 100 to about 1000 psig. in the presence of a catalytically effective amount of a soluble molybdenum catalyst. A liquid stream comprising tertiary butyl alcohol is recovered from the reaction mixture and fed to a decomposition zone wherein the tertiary butyl hydroperoxide contained therein is decomposed by "hot aging" at 250.degree.-350.degree. F. at a pressure lower than the pressure in the oxidation zone. The tertiary butyl alcohol can be further subjected to a clean-up treatment at 375.degree.-475.degree. F. for 1 to 10 minutes. Worrell et al. in U.S. Pat. No. 4,296,263 discloses a related process wherein the feedstock is a mixture of normal butane with isobutane and wherein the oxidation catalyst is a soluble form of chromium, cobalt, nickel, manganese, molybdenum, or a mixture thereof.
The metal phthalocyanines are known compounds, described for example in the ACS Monograph Series of F. H. Moser and A. L. Thomas entitled "Phthalocyanine Compounds" (Rhinehold Publishing Corp.).
Williams et al. U.S. Pat. No. 3,816,548 is directed to a liquid phase oxidation process for oxidizing an isoparaffin hydrocarbon such as isobutane to an alcohol such as tertiary butyl alcohol in the presence of certain metal phthalocyanine catalysts.
Allison et al. U.S. Pat. No. 3,505,360 states that it has been reported that cyclohexenyl hydroperoxide has been decomposed to provide cyclohexanone and cyclohexanol in the presence of ferrous phthalocyanine.
Ohkatsu et al., in an article entitled "The Liquid-Phase Oxidation of Acetaldehyde with Metal Phthalocyanines. Solvent Effect", Bulletin of the Chemical Society of Japan,Vol. 50 (3) 696-700 (1977), report on their investigation of the effect of the solvent used when oxidizing acetaldehyde with oxygen using a metal phthalocyanine catalyst and their conclusion that the solvent effects the rate of oxidation in two ways, one based on the prevention of the oxygen molecules from coordinating with the metal phthalocyanine and the other due to the solvation with the activated oxygen molecules on the catalyst molecule. Preferred solvents were ethyl acetate, bromobenzene, benzene and acetone.
Sheng et al., in an article entitled "Hydroperoxide Oxidations Catalyzed by Metals",Advances in Chemistry Series,76, 418 (1968), conclude that in the reaction of an organic hydroperoxide with an olefin in the presence of a vanadium, molybdenum or tungsten catalyst, the conversion and epoxide yield are higher, in general, as the polarity of the solvent decreases. Benzene was one of the solvents that was used.
An article entitled "Metal-Catalyzed Epoxidation of Olefins with Organic Hydroperoxides" by Sheldon et al., Journal of Catalysts,31, 427 -437 (1979) on pages 30 and 31, reports on the results obtained by the Metal-Catalyzed Decomposition of Tertiary Butyl Hydroperoxide in the absence of an olefin including the decomposition of tertiary butyl hydroperoxide in solution in benzene in the presence of Mo, Ti, W and Cr catalysts to provide tertiary butyl alcohol and oxygen.